<template>
  <div>
      <router-link
              tag="div"
              to="/"
              class="header-abs"
              v-show="showDbs"
      >
      <div class="iconfont header-abs-back">&#xe624;</div>
      </router-link>
      <div class="header-fixed"
           v-show="!showDbs"
           :style="opacityStyle"
      >
        <div class="iconfont header-fixed-back">&#xe624;</div>
        景点详情
      </div>

  </div>
</template>

<script>
export default {
  name: "DetailHeader",
  data() {
    return {
      showDbs: true,
      opacityStyle: {
        opacity: 0
      }
    };
  },
  methods: {
    handleScroll() {
      const top = document.documentElement.scrollTop;
      if (top > 60) {
        let opacity = top / 140;
        opacity = opacity > 1 ? 1 : opacity;
        this.opacityStyle = { opacity };
        this.showDbs = false;
      } else {
        this.showDbs = true;
      }
    }
  },
  activated() {
    window.addEventListener("scroll", this.handleScroll);
  },
  deactivated () {
    window.removeEventListener('scroll', this.handleScroll)
  }
};
</script>

<style scoped lang="stylus">
@import '~styles/varibles.styl';

.header-abs {
  position: absolute;
  left: 0.2rem;
  top: 0.2rem;
  width: 0.8rem;
  height: 0.8rem;
  line-height: 0.8rem;
  border-radius: 0.4rem;
  text-align: center;
  background: rgba(0, 0, 0, 0.8);
}

.header-abs-back {
  color: #fff;
  font-size: 0.4rem;
}

.header-fixed {
  z-index: 2;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: $headerHeight;
  line-height: $headerHeight;
  text-align: center;
  color: #fff;
  background: $bgColor;
  font-size: 0.32rem;

  .header-fixed-back {
    position: absolute;
    top: 0;
    left: 0;
    width: 0.64rem;
    text-align: center;
    font-size: 0.4rem;
    color: #fff;
  }
}
</style>
